81311444000 has 48 divisors (see below), whose sum is σ = 199782227736. Its totient is φ = 32524576000.

The previous prime is 81311443987. The next prime is 81311444003. The reversal of 81311444000 is 44411318.

It can be written as a sum of positive squares in 4 ways, for example, as 9806544784 + 71504899216 = 99028^2 + 267404^2 .

It is a super-2 number, since 2×81311444000² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81311444003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10159931 + ... + 10167930.

Almost surely, 2^81311444000 is an apocalyptic number.

81311444000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81311444000 is an abundant number, since it is smaller than the sum of its proper divisors (118470783736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81311444000 is a wasteful number, since it uses less digits than its factorization.

81311444000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20327886 (or 20327868 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

Adding to 81311444000 its reverse (44411318), we get a palindrome (81355855318).

The spelling of 81311444000 in words is "eighty-one billion, three hundred eleven million, four hundred forty-four thousand".